Highly multiplexed and quantitative gene expression assays, capable of precisely measuring hundreds of transcripts provide a robust approach with broad applicability for monitoring the human immune system. There is a strong demand for technologies which bridge the gap between microarrays, which are good for broad surveys of thousands of genes, but are weak on quantitation, and PCR methods which are strong on quantitation, but have limited multiplexing capability. We will create a unique infrastructure/resource designed to accelerate scientific progress in the field of immune monitoring. We will develop biological content and establish the nCounter digital gene expression system from NanoString as a preferred platform. We will apply the platform to samples provided from investigators under the U19 project in vaccination and response to infection. The core will be available for other studies as well. The core will generate synergy and foster interactions among multi and interdisciplinary research teams that will advance public health and health care delivery.